Molding is a process by virtue of which a molded article can be formed from molding material by using a molding system. Various molded articles can be formed by using the molding process, such as an injection molding process. One example of a molded article that can be formed, for example, from polyethelene terephalate (PET) material is a preform that is capable of being subsequently blown into a beverage container, such as, a bottle and the like.
As an illustration, injection molding of PET material involves heating the PET material (ex. PET pellets, PEN powder, PLA, etc.) to a homogeneous molten state and injecting, under pressure, the so-melted PET material into a molding cavity defined, at least in part, by a female cavity piece and a male core piece mounted respectively on a cavity plate and a core plate of the mold. The cavity plate and the core plate are urged together and are held together by clamp force, the clamp force being sufficient enough to keep the cavity and the core pieces together against the pressure of the injected PET material. The molding cavity has a shape that substantially corresponds to a final cold-state shape of the molded article to be molded. The so-injected PET material is then cooled to a temperature sufficient to enable ejection of the so-formed molded article from the mold. When cooled, the molded article shrinks inside of the molding cavity and, as such, when the cavity and core plates are urged apart, the molded article tends to remain associated with the core piece. Accordingly, by urging the core plate away from the cavity plate, the molded article can be demolded, i.e. ejected off of the core piece. Ejection structures are known to assist in removing the molded articles from the core halves. Examples of the ejection structures include stripper plates, ejector pins, robots, etc.
One consideration for economical operation of the molding system is cycle time or, in other words, time that elapses between a point in time when the cavity and core halves are closed and the molded articles are formed and a subsequent point in time when they are opened and the molded articles are removed. As one will appreciate, the shorter the cycle time, the higher the number of molded articles that can be produced in a particular mold in a given time. One attempt to minimize the cycle time is a so-called “post-mold cooling” process. Generally speaking, the post-mold cooling process involves removing the molded articles from the mold once they are sufficiently cooled to enable ejection of the molded articles without causing significant deformation to the molded articles during its transfer to an auxiliary cooling structure. Post mold cooling then occurs independently (but in parallel) to the injection cycle of the molding machine. As an example, the auxiliary cooling structure includes a plurality of cooling tubes mounted onto a take-off plate with vacuum service and cooling service being supplied to the cooling tubes from a source of vacuum service and cooling service connected to the take-off plate. The take-off plate comprises an interface for mounting the take-off plate to a robot and, within this configuration, is typically referred to by those of skill in the art as an “End Of Arm Tool” (EOAT).
Naturally, a layout of the EOAT has to correspond to a layout of the core pieces in the mold. It is known to have molds with varying numbers of molding cavities. Furthermore, an entity operating the molding system may choose to change the size of the mold in the system already in operation. In line with business consideration, the entity operating the molding system may choose to increase or decrease cavitation by, for example, installing a different mold within the molding system. It should be clear that if a new mold has a cavitation different from a cavitation of the old mold, the entity operating the molding system also needs to change the EOAT to accommodate the differing layout of mold cavities. A typical approach to changing configuration of the EOAT is to remove an old EOAT (i.e. the EOAT complementary to the old mold) and replace it with a new EOAT (i.e. the EOAT complementary to the new mold). As part of changing the EOAT, a calibration process is carried out to ensure that the new EOAT will correctly cooperate with other components of the molding system. For example, a technician (or another person) calibrating the new EOAT may need to ensure that lateral movement of the new EOAT into and out of the open mold will not interfere with or otherwise damage other parts of the molding system.
Due to business considerations and as is appreciated by those skilled in the art, it is desirable to minimize time and costs taken to replace the EOAT. Some prior art solutions have attempted to mitigate this time problem by providing a quick change interface between the EOAT and the robot to enable the technician (or another person) to quickly exchange the old EOAT for the new EOAT. However, even within this solution, the technician (or another person) will need to spend time to calibrate the new EOAT.